U.S. patent application number 14/048071 was filed with the patent office on 2014-02-06 for laundry treating appliance with controlled mechanical energy.
This patent application is currently assigned to Whirlpool Corporation. The applicant listed for this patent is Whirlpool Corporation. Invention is credited to FARHAD ASHRAFZADEH, RYAN R. BELLINGER, DUANE M. KOBOS, RICHARD A. SUNSHINE.
Application Number | 20140033556 14/048071 |
Document ID | / |
Family ID | 43430257 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140033556 |
Kind Code |
A1 |
ASHRAFZADEH; FARHAD ; et
al. |
February 6, 2014 |
LAUNDRY TREATING APPLIANCE WITH CONTROLLED MECHANICAL ENERGY
Abstract
A laundry treating appliance and a method for operating a
laundry treating appliance having a rotatable drum defining a
chamber for receiving laundry. The operation of the laundry
treating appliance may be based on the mechanical energy due to the
falling action of the laundry.
Inventors: |
ASHRAFZADEH; FARHAD;
(BOWLING GREEN, KY) ; BELLINGER; RYAN R.; (SAINT
JOSEPH, MI) ; KOBOS; DUANE M.; (LAPORTE, IN) ;
SUNSHINE; RICHARD A.; (GRANGER, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Whirlpool Corporation |
Benton Harbor |
MI |
US |
|
|
Assignee: |
Whirlpool Corporation
Benton Harbor
MI
|
Family ID: |
43430257 |
Appl. No.: |
14/048071 |
Filed: |
October 8, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12507286 |
Jul 22, 2009 |
8578532 |
|
|
14048071 |
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Current U.S.
Class: |
34/90 ;
68/12.02 |
Current CPC
Class: |
D06F 2204/06 20130101;
D06F 58/20 20130101; D06F 25/00 20130101; D06F 34/22 20200201; D06F
35/006 20130101; D06F 2202/10 20130101 |
Class at
Publication: |
34/90 ;
68/12.02 |
International
Class: |
D06F 39/00 20060101
D06F039/00; D06F 25/00 20060101 D06F025/00; D06F 58/20 20060101
D06F058/20 |
Claims
1-18. (canceled)
19. A laundry treating appliance for applying a treating cycle of
operation to a load of laundry, comprising: a rotatable drum
defining a chamber for receiving laundry; a motor operably coupled
to and configured to rotate the drum; and a controller operably
coupled to the motor and configured to determine a cumulative value
indicative of the cumulative mechanical energy due to the falling
action of the laundry and to terminate at least a portion of the
treating cycle based on a comparison of the cumulative value with a
predetermined threshold value of mechanical energy to be imparted
to the laundry during the treating cycle that is a function of at
least one of a laundry type and a load size.
20. The method of claim 19 wherein the laundry treating appliance
is one of a clothes washer, a clothes dryer, and a combination
washer/dryer.
21-34. (canceled)
35. A laundry treating appliance for applying a treating cycle of
operation to a load of laundry, comprising: a rotatable drum
defining a chamber for receiving laundry; a motor operably coupled
to and configured to rotate the drum; and a controller operably
coupled to the motor and configured to determine a rotational speed
of the drum at which mechanical energy due to falling action is
transmitted to laundry at a predetermined rate and to control the
operation of the motor to rotate the drum based on the rotational
speed.
36. The method of claim 35 wherein the laundry treating appliance
is one of a clothes washer, a clothes dryer, and a combination
washer/dryer.
37. The method of claim 35 wherein the predetermined rate comprises
a rate that substantially maximizes the mechanical energy
transmitted to the laundry.
38-48. (canceled)
49. A laundry treating appliance for applying a treating cycle of
operation to a load of laundry, comprising: a rotatable drum
defining a chamber for receiving laundry; a motor operably coupled
to and configured to rotate the drum; and a controller operably
coupled to the motor and configured to determine a value indicative
of the mechanical energy due to the falling action of the laundry
based on a crest factor of a motor torque waveform for the motor
and to control the operation of the laundry treating appliance
based on the determined value.
50. The method of claim 49 wherein the laundry treating appliance
is one of a clothes washer, a clothes dryer, and a combination
washer/dryer.
Description
BACKGROUND OF THE INVENTION
[0001] A laundry treating appliance is a common household device
for treating articles in accordance with a treating cycle, and
includes clothes washing machines and clothes dryers. A clothes
washing machine cleans loads of articles, such as clothing and
other fabric items, in accordance with a preprogrammed wash
cycle.
[0002] For automatic washers, there are three primary sources of
cleaning action: mechanical action, chemical action, and thermal
action. All other things being equal, any change in one or more of
these actions requires a corresponding offsetting change in the
other actions to obtain the same degree of cleaning
effectiveness.
[0003] Automatic washing machines can generally be categorized as
horizontal axis machines or vertical axis machines. Horizontal axis
machines are sometimes referred to as "front loaders" and comprise
a perforated drum located within an imperforate tub, with the drum
rotating about a generally horizontal axis, although the axis can
be canted relative to the horizontal.
[0004] Vertical axis and horizontal axis machines differ in the
manner in which they impart mechanical energy to the laundry.
Vertical axis machines tend to use an impeller or agitator that
directly impacts the laundry to impart mechanical energy.
Horizontal axis machines impart mechanical energy primarily by the
tumbling of the articles in the drum as the drum rotates.
[0005] The different manners for imparting mechanical energy
results in different operational consequences. One consequence is
that horizontal axis machines impart much less mechanical energy to
the laundry than vertical axis machines. Another of which is that
it is practical to determine the amount of mechanical energy
imparted in a vertical axis machine and impractical to determine in
a horizontal axis machine. The direct contact of the
impeller/agitator to the laundry to impart the mechanical energy in
a vertical axis machine as compared to the tumbling of the laundry
in a horizontal axis machines provides for direct sensing through
the forces of the impeller/agitator as a means for determining the
imparted mechanical action forces, which is not possible with the
horizontal axis machines.
SUMMARY OF THE INVENTION
[0006] The invention relates to a laundry treating appliance and a
method of operating a laundry treating appliance based on the
mechanical energy due to the falling action of the laundry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In the drawings:
[0008] FIG. 1 is a perspective view of an exemplary laundry
treating appliance in the form of a washing machine according to
one embodiment.
[0009] FIG. 2 is a schematic view of the washing machine of FIG. 1
according to one embodiment.
[0010] FIG. 3 is a schematic view of a control system according to
one embodiment for the washing machine of FIGS. 1 and 2.
[0011] FIG. 4 is a schematic view of a drum of the washing machine
from FIG. 1 and a load inside the drum according to one
embodiment.
[0012] FIGS. 5A-5C show graphs of the motor torque signature during
tumbling in a horizontal-axis washing machine, wherein the motor
torque is shown in a time domain for loads of polyester cloth
having a dry mass of about 1 kg, 3 kg, and 5 kg, respectively.
[0013] FIG. 6 is a flow chart illustrating one embodiment of a
method according to the invention for determining when to terminate
a portion of a treating cycle in a washing machine.
[0014] FIG. 7 is a flow chart illustrating one embodiment of a
method according to the invention for determining a rotational
speed of a drum of a washing machine that will cause a desired
amount of mechanical energy to be transmitted to a load by falling
action.
[0015] FIG. 8 is a flow chart illustrating one embodiment of a
method according to the invention for optimizing the rotational
speed of a drum of a washing machine.
DESCRIPTION OF AN EMBODIMENT OF THE INVENTION
[0016] Referring now to the figures, FIG. 1 is a perspective view
of an exemplary laundry treating appliance in the form of a washing
machine 10 according to one embodiment of the invention. The
methods described herein may be used with any suitable laundry
treating appliance and are not limited to use with washing
machines, including the washing machine 10 described below and
shown in the drawings. The washing machine 10 is described and
shown for illustrative purposes. The laundry treating appliance may
be any machine that treats articles such as clothing or fabrics,
and examples of the laundry treating appliance may include, but are
not limited to, a washing machine, including top-loading,
front-loading, and horizontal axis washing machines; a dryer, such
as a tumble dryer or a stationary dryer, including top-loading
dryers and front-loading dryers; a combination washing machine and
dryer; a tumbling or stationary refreshing/revitalizing machine; an
extractor; a non-aqueous washing apparatus; and a revitalizing
machine. For illustrative purposes, the method will be described
with respect to a washing machine with one or more articles making
up the load, with it being understood that the invention may be
adapted for use with other types of laundry treating
appliances.
[0017] Washing machines are typically categorized as either a
vertical axis washing machine or a horizontal axis washing machine.
As used herein, the "vertical axis" washing machine refers to a
washing machine having a rotatable drum that rotates about a
generally vertical axis relative to a surface that supports the
washing machine. In some vertical axis washing machines, the drum
rotates about a vertical axis generally perpendicular to a surface
that supports the washing machine. However, the rotational axis
need not be perfectly vertical or perpendicular to the surface. The
drum can rotate about an axis inclined relative to the vertical
axis. As used herein, the "horizontal axis" washing machine refers
to a washing machine having a rotatable drum that rotates about a
generally horizontal axis relative to a surface that supports the
washing machine. In some horizontal axis washing machines, the drum
rotates about a horizontal axis generally parallel to a surface
that supports the washing machine. However, the rotational axis
need not be perfectly horizontal or parallel to the surface. The
drum can rotate about an axis inclined relative to the horizontal
axis, with fifteen degrees of inclination being one example of
inclination.
[0018] Vertical axis and horizontal axis machines can be
differentiated by the manner in which they impart mechanical energy
to the load. In vertical axis machines, an article moving element
moves within the drum to impart mechanical energy directly to the
load or indirectly through wash liquid in the drum. In horizontal
axis machines, mechanical energy is typically imparted to the load
by tumbling the load resulting from rotating the drum. The tumbling
involves repeated lifting and dropping of the articles in the load.
The illustrated washing machine 10 of FIGS. 1 and 2 is a horizontal
axis washing machine.
[0019] FIG. 2 provides a schematic view of the washing machine 10
of FIG. 1. The washing machine 10 may include a cabinet 12 that
houses a stationary tub 14, which defines an interior chamber 16. A
rotatable drum 18 may be mounted within the interior chamber 16 of
the tub 14 and may include a plurality of perforations 20, such
that liquid may flow between the tub 14 and the drum 18 through the
perforations 20. The drum 18 defines a laundry treatment chamber 22
sized to hold a load, which may have one article or a plurality of
articles. The drum 18 may further include a plurality of baffles 24
disposed on an inner surface of the drum 18 to lift the load
contained in the laundry treatment chamber 22 while the drum 18
rotates. Depending on the various characteristics of the washing
machine 10, such as the size of the drum 18 and the size of the
load, the rotation of the drum 18 may result in various types of
load movement inside the drum 18. For example, the load may undergo
at least one of tumbling, rolling (also called balling), sliding,
satellizing (also called plastering), and combinations thereof. The
terms tumbling, rolling, sliding and satellizing are terms of art
that may be used to describe the motion of some or all of the
articles. However, not all of the articles forming the load must
exhibit the motion for the load to be described accordingly.
[0020] The drum 18 may be coupled with a motor 26 having a stator
27 and a rotor 28 through a drive shaft 30 for selective rotation
of the treating chamber 22 during a cycle of operation. The motor
26 may rotate the drum 18 at various speeds in either rotational
direction. Both the tub 14 and the drum 18 may be selectively
closed by a door 32. A bellows 34 couples an open face of the tub
14 with the cabinet 12, and the door 32 seals against the bellows
34 when the door 32 closes the tub 14.
[0021] A controller 70 may be coupled with various working
components of the washing machine 10 to control the operation of
the washing machine 10. The controller 70 can be operably coupled
to a control panel 36 with a user interface provided on the
exterior of the cabinet 12 that may include one or more knobs,
switches, displays, and the like for communicating with the user,
such as to receive input and provide output.
[0022] While the illustrated washing machine 10 includes both the
tub 14 and the drum 18, with the drum 18 defining the laundry
treatment chamber 22, it is within the scope of the invention for
the laundry treating appliance to include only one receptacle, with
the receptacle defining the laundry treatment chamber for receiving
the load to be treated.
[0023] The washing machine 10 of FIG. 2 may further include a
liquid supply and recirculation system. Liquid, such as water, may
be supplied to the washing machine 10 from a water supply 40, such
as a household water supply. A supply conduit 42 may fluidly couple
the water supply 40 to a detergent dispenser 44. An inlet valve 46
may control flow of the liquid from the water supply 40 and through
the supply conduit 42 to the detergent dispenser 44. A liquid
conduit 48 may fluidly couple the detergent dispenser 44 with the
tub 14. The liquid conduit 48 may couple with the tub 14 at any
suitable location on the tub 14 and is shown as being coupled to a
front wall of the tub 14 in FIG. 2 for exemplary purposes. The
liquid that flows from the detergent dispenser 44 through the
liquid conduit 48 to the tub 14 typically enters a space between
the tub 14 and the drum 18 and may flow by gravity to a sump 50
formed in part by a lower portion of the tub 14. The sump 50 may
also be formed by a sump conduit 52 that may fluidly couple the
lower portion of the tub 14 to a pump 54. The pump 54 may direct
fluid to a drain conduit 56, which may drain the liquid from the
washing machine 10, or to a recirculation conduit 58, which may
terminate at a recirculation inlet 60. The recirculation inlet 60
may direct the liquid from the recirculation conduit 58 into the
drum 18. The recirculation inlet 60 may introduce the liquid into
the drum 18 in any suitable manner, such as by spraying, dripping,
or providing a steady flow of the liquid.
[0024] The liquid supply and recirculation system may further
include one or more devices for heating the liquid such as a steam
generator 62 and/or a sump heater 64. The steam generator 62 may be
provided to supply steam to the treating chamber 22, either
directly into the drum 18 or indirectly through the tub 14 as
illustrated. The valve 46 may also be used to control the supply of
water to the steam generator 62. The steam generator 62 is
illustrated as a flow through steam generator, but may be other
types, including a tank type steam generator. Alternatively, the
heating element 64 may be used to generate steam in place of or in
addition to the steam generator 62. The steam generator 62 may be
controlled by the controller 70 and may be used to heat to the load
as part of a treating cycle, much in the same manner as heating
element 64. The steam generator 62 may also be used to introduce
steam to treat the load as compared to merely heating the load.
[0025] Additionally, the liquid supply and recirculation system may
differ from the configuration shown in FIG. 2, such as by inclusion
of other valves, conduits, wash aid dispensers, sensors, such as
water level sensors and temperature sensors, and the like, to
control the flow of liquid through the washing machine 10 and for
the introduction of more than one type of detergent/wash aid.
Further, the liquid supply and recirculation system need not
include the recirculation portion of the system or may include
other types of recirculation systems.
[0026] Referring now to FIG. 3, which is a schematic view of an
exemplary control system 68 of the washing machine 10, the
controller 70 may be coupled to various working components of the
washing machine 10, such as the pump 54, the motor 26, the inlet
valve 46, and the detergent dispenser 44, to control the operation
of the washing machine 10. The controller 70 may further be coupled
to the steam generator 62 and/or a sump heater 64 if either is
provided. The controller 70 may receive data from one or more of
the working components and may provide commands, which can be based
on the received data, to one or more of the working components to
execute a desired operation of the washing machine 10. The commands
may be data and/or an electrical signal without data. The control
panel 36 may be coupled to the controller 70 and may provide for
input/output to/from the controller 70. In other words, the control
panel 36 may perform a user interface function through which a user
may enter input related to the operation of the washing machine 10,
such as selection and/or modification of an operation cycle of the
washing machine 10, and receive output related to the operation of
the washing machine 10.
[0027] Many known types of controllers may be used for the
controller 70. The specific type of controller is not germane to
the invention. It is contemplated that the controller is a
microprocessor-based controller that implements control software
and sends/receives one or more electrical signals to/from each of
the various working components to effect the control software. As
an example, proportional control (P), proportional integral control
(PI), and proportional derivative control (PD), or a combination
thereof, a proportional integral derivative control (PID control),
may be used to control the various components.
[0028] The washing machine 10 may perform one or more manual or
automatic treating cycles, and a common treating cycle includes a
wash phase, a rinse phase, and a spin extraction phase. Other
phases for treating cycles include, but are not limited to,
intermediate extraction phases, such as between the wash and rinse
phases, and a pre-wash phase preceding the wash phase, and some
treating cycles include only a select one or more of these
exemplary phases. In a horizontal axis washing machine, the drum
may be rotated during any one of these phases to effect tumbling of
the articles making up the load. In particular tumbling may be
combined with a wash phase to create a tumble wash phase.
Regardless of the phases employed in the treating cycle, the
methods described below may relate to determining an optimized
rotational speed.
[0029] Before specific embodiments of the methods are presented, a
description of theory behind the methods may be constructive. In a
washing machine, the articles making up the load are cleaned by
three main sources of energy: chemical, thermal, and mechanical.
Referring to FIG. 4, which is a schematic view of the drum 18 and a
load 80 in the drum 18, mechanical energy can further be divided
into two components: article-to-article friction and the falling
associated with the tumbling of articles due to the rotation of the
drum 18, which is a greater source of mechanical energy than the
article-to-article friction. During tumbling, articles 82 making up
the load 80 rotate with the drum 18 from a lower position,
generally near or at the bottom of the drum 18, to a raised
position above the lower position, where the article is no longer
being lifted by the drum 18 and falls within the drum 18, generally
toward the bottom of the drum 18. The rotation of the articles with
the drum 18 may be facilitated by the baffles 24. The point at
where the article separates from the drum 18 and falls by gravity,
illustrated by arrow A, to the nadir of the drum 18 is the function
of several parameters, including, without limitation, the
centrifugal force acting on the article, which varies with speed of
rotation, illustrated by arrow B. During tumbling, the individual
articles 82 may move relative to one another such that the articles
may rub against each other and may fall onto each other as they
fall to the lower position of the drum 18. This accounts for
creating article-to-article friction.
[0030] The tumbling motion of the articles 82 is irregular. For
example, some articles 82 may fall during one rotation of the drum
18 and not the next due to tangling or twisting of the articles 82.
Each lifting/falling action changes the load on the motor 26 (FIG.
2), and thus creates a change in the motor torque, which can be
seen in a motor torque signature. The change in motor torque is
related to the dynamic change in the mass of the laundry that the
motor must rotate. As each article is lifted, the motor torque is
affected by the article's mass. However, when each article falls,
the article has separated from the drum and the article's mass is
temporarily not "seen" by the motor and the motor torque is not
impacted by the falling article. Of course, the actual movement of
a laundry load comprising multiple articles is more complex than
the description of a single article because the interaction of the
multiple laundry articles may interfere with a complete separation
of a particular article.
[0031] One challenge in using the motor torque signature to
identify falling action is that a load imbalance will also create a
variation in the motor torque signature. Thus, it is necessary to
distinguish motor torque variations caused by falling action, and
those attributable to load imbalance. Distinguishing between load
imbalance and falling action becomes more difficult for larger
loads, since there may be little or no falling action because the
drum 18 is more packed.
[0032] It has been found that a more sinusoidal motor torque
signature indicates a load imbalance, rather than falling action,
which is non-sinusoidal. FIGS. 5A-5C show exemplary experimental
data of the motor torque as a function of time (i.e., in the time
domain) for 1 kg, 3 kg, and 5 kg dry mass loads of polyester cloth
during tumbling in a horizontal-axis washing machine, respectively.
In the graphs, the time axis (i.e., the x-axis) is provided as an
"Index" rather than "Time" due to the manner of recording
experimental data. In the graphs, after an initial maximum peak at
the initial start-up, the motor torque signature settles into a
varying pattern containing peaks and valleys. The motor torque
signature varies depending on whether there is a falling action,
and also whether there is a load imbalance. For the exemplary 5 kg
load, which has a more sinusoidal motor torque signature than the 1
kg or 3 kg loads, there is no falling action, but there is a load
imbalance. Thus, the waveform of the motor torque signature can be
used to distinguish between load imbalance and falling action.
[0033] One way to distinguish between sinusoidal and non-sinusoidal
waveforms is by determining the crest factor of the waveform. The
crest factor, or peak-to-average ratio (PAR), is a measurement of a
waveform, calculated from the peak amplitude of the waveform
divided by the RMS (time-averaged) value of the waveform, and can
be expressed by the following equation:
C = x peak x RMS ##EQU00001##
The crest factor is minimum for a sinusoidal waveform, and
increases as a waveform becomes more non-sinusoidal; thus, a larger
crest factor indicates that there is falling action of the articles
and the relative magnitude of the crest factor is indicative of the
relative amount of falling action.
[0034] The method of the invention can use the crest factor of the
motor torque signature to distinguish between load imbalance and
falling action. If the crest factor indicates that there is falling
action, then the motor torque signature can be used to determine
the degree of mechanical falling action being transferred to the
articles in the drum. This can be estimated or inferred from the
area underneath the motor torque signature waveform. The area can
be viewed as a measurement system for the mechanical energy due to
falling action imparted to the articles.
[0035] This measurement system can be used to control the
rotational speed of the drum to control the amount of mechanical
energy imparted by falling action to the laundry. For example, if
it is desired to maximize the amount of mechanical energy, the
rotational speed can be varied, e.g. increased or decreased, until
the crest factor has been maximized. When the crest factor is
maximized, the mechanical energy due to falling action being
imparted to the articles is also maximized. Maximizing the
mechanical energy may be useful to shorten the cycle time or when
the laundry is of a more robust material. However, the amount of
mechanical energy may be controlled to ensure lesser amounts of
mechanical energy are imparted to the laundry, such as when the
laundry is of a more delicate fabric.
[0036] This measurement system can also be used to determine when
to terminate the treating cycle. For example, the mechanical energy
due to falling action can be measured over time and, when the
accumulated mechanical energy (area under the motor torque
signature waveform) due to falling action has reached a
predetermined value, a phase of the treating cycle or the entire
treating cycle can be terminated. The predetermined value may be
the minimum amount of mechanical energy due to falling action that
sufficiently cleans the articles. Thus, this method optimizes the
treating cycle to achieve a good cleaning performance while
minimizing wear on the articles. Each treating cycle or each
treating cycle phase may be provided with a predetermined
mechanical energy that, when satisfied, may be used alone or in
combination with other parameters to terminate the treating cycle
or treating cycle phase.
[0037] FIG. 6 provides a flow chart of an embodiment of a method 90
that employs the above theory to determine when to terminate a
portion of a treating cycle in a washing machine. The sequence of
steps depicted is for illustrative purposes only and is not meant
to limit the method 90 in any way as it is understood that the
steps may proceed in a different logical order, additional or
intervening steps may be included, or described steps may be
divided into multiple steps, without detracting from the invention.
The method 90 may be incorporated into a treating cycle of the
washing machine 10, such as during a specific treating phase, for
example a wash phase or a tumble wash phase, or may be performed
independently from a treating cycle. It is assumed that a load of
one or more articles has been placed within the drum 18 prior to
commencement of the method 90.
[0038] The method 90 may begin with at 92 with rotating the drum
18. Rotating of the drum 18 may occur subsequent to or
simultaneously with wetting of the load by the liquid supply and
recirculation system (FIG. 2). In the washing machine 10 of FIG. 2,
the motor 26 may drive the rotation of the drum 18. The drum 18 may
rotate at a speed suitable to induce tumbling of the load.
[0039] At 94, a determination of a cumulative value indicative of
cumulative mechanical energy due to falling action may occur
subsequent to or simultaneously with the rotating of the drum 18 by
the motor 26 at 92. The cumulative value can be determined by
determining a crest factor of a motor torque waveform for the motor
26 rotating the drum 18. As discussed above, this helps distinguish
between falling action and a load imbalance. If the crest factor
indicates that there is falling action of the articles, then the
area beneath the motor torque waveform for the motor 26 can be used
to determine the degree of mechanical falling action being
transferred to the articles in the drum. This area or the degree of
mechanical falling action determined from the area can be
accumulated or summed over time to determine the cumulative value.
The determination of the cumulative value can be carried out by the
controller 70.
[0040] At 96, the cumulative value determined at 94 is compared
with a predetermined threshold value. The threshold value is a
reference value to compare with the cumulative value to determine
whether to terminate at least a portion of the treating cycle. The
threshold value may be a desired value of mechanical energy to
impart to the laundry during the treating cycle.
[0041] The threshold value may be a function of at least one a
laundry type and a load size, either of which can be a quantitative
or qualitative value. One example of quantitative laundry type is
the article's material, such as cotton, silk, or polyester.
Examples of qualitative laundry type are delicates, permanent
press, or heavy duty. Examples of quantitative load sizes are the
mass, volume, or surface area of the load, or the number of
articles making up the load. Examples of qualitative load sizes are
extra-small, small, medium, large, or extra-large.
[0042] The threshold value may be predetermined, or may be
determined for each load or treating cycle. For the later case, the
threshold value may be automatically determined for the load, or
may be manually set by the user. For the former case, the
controller 70 may be loaded with one or more predetermined
threshold values during manufacture.
[0043] The comparison may be carried out by the controller 70 and
may be based on a predetermined relationship between the cumulative
value and the threshold value. Based on the comparison, the method
90 may return to 94 to determine the cumulative value again, or may
terminate at least a portion of the treating cycle. One example of
a predetermined relationship is illustrated at 98 and 100. If it is
determined that the cumulative value is below the threshold value,
as shown at 98, the method 90 returns to 94. If it is determined
that the cumulative value is at or above the threshold value, as
shown at 100, the method 90 continues to 102, and at least a
portion of the treating cycle is terminated.
[0044] Termination of at least a portion of the treating cycle may
entail terminating a treating phase of the treating cycle, such as
a tumble wash phase, or may entail terminating the treating cycle
entirely. Termination of at least a portion of the treating cycle
may alternately entail setting the duration of a treating phase or
the treating cycle.
[0045] While not illustrated as part of the method 90, the
cumulative value determined at 94 may be used to determine an
operating rotational speed of the drum 18. If the cumulative value
is determined from the crest factor, the rotational speed can be
varied until the crest factor has been maximized, at which speed
substantially maximum mechanical energy is imparted to articles in
the load. The crest factor can also be determined for rotational
speeds other than the maximum mechanical energy. It is contemplated
to select a rotation speed less than, such as a percentage of, the
rotational speed associated with the maximum crest factor. It is
also contemplated to create a crest factor versus rotational speed
profile for a given laundry load and to select the most
advantageous rotational speed for a given load based on the
profile.
[0046] It should be noted that while this description is written in
absolute terms, such as determining the maximum crest factor, in
practice, it is likely and often unnecessary to determine the
absolute value of any parameter or value described. For example, it
is contemplated that digital sampling techniques will be used,
which may well miss the absolute maximum crest factor. However, the
maximum crest factor as determined under such techniques will be
close enough for a practical application of the invention.
[0047] FIG. 7 provides a flow chart of an embodiment of a method
110 that employs the above theory to determine a rotational speed
of the drum 18 that will cause a desired amount of mechanical
energy to be transmitted to a load by falling action. The sequence
of steps depicted is for illustrative purposes only and is not
meant to limit the method 110 in any way as it is understood that
the steps may proceed in a different logical order, additional or
intervening steps may be included, or described steps may be
divided into multiple steps, without detracting from the invention.
The method 110 may be incorporated into a treating cycle of the
washing machine 10 or may be performed independently from a
treating cycle. It is assumed that a load of one or more articles
has been placed within the drum 18 prior to commencement of the
method 110.
[0048] The method 110 may begin at 112 by setting a rate of
mechanical energy due to be transmitted to the load by falling
action. The rate may be set by the user through the one or more
user inputs using the user interface 36, such as by the selection
of a treating cycle. From the user input, the rate may be
automatically determined by the controller 70. The controller 70
may store different rates associated with particular treating
cycles or a particular combination of user inputs, or may have a
scheme for calculating the rate from the user input. The rate may
be a function of at least one a laundry type and a load size,
either of which can be a quantitative or qualitative value as
described above. For example, if the user selects a `delicate`
treating cycle, the rate may be lower than if the user selected a
`heavy duty` treating cycle, since `delicate` article are more
subject to wear than `heavy duty` articles.
[0049] The rate can be one that substantially maximizes the
mechanical energy transmitted to the articles, such as through
falling action of the articles as the drum 18 is rotated. By
maximizing mechanical energy, the duration of the treating cycle or
a portion of the treating cycle may be reduced since articles may
be cleaned in less time.
[0050] At 114, a rotational speed S for the drum 18 is determined
based on the rate set at 112. The rotational speed S may be a speed
suitable to induce tumbling of the load wherein the load is subject
to falling action. The rotational speed S can be determined by
determining a crest factor of a motor torque waveform for the motor
26 rotating the drum 18. By increasing or decreasing the rotational
speed of the drum 18 until the crest factor is maximized, the
mechanical energy due to falling action being imparted to the
articles is also maximized. Thus, the rotational speed when the
crest factor is maximized can be considered a maximum mechanical
energy rotational speed.
[0051] At 116, the drum 18 is rotated at the rotational speed S
determined at 114. Rotation of the drum 18 may occur subsequent to
or simultaneously with wetting of the load by the liquid supply and
recirculation system (not shown). Rotation of the drum 18 may occur
subsequent to or simultaneously with a particular treating phase of
a treating cycle, such as a tumble wash phase.
[0052] In the washing machine 10 of FIG. 2, the controller 70 may
control the motor 26 to drive the rotation of the drum 18 at the
rotational speed S. According to one embodiment, the motor 26
rotates the drum 18 at a steady state for at least part of the
determination at 114. For example, the rotational speed S may be a
constant speed setpoint, wherein the motor 26 is controlled to
rotate the drum 18 according to the setpoint, while the actual
speed of the drum 18 fluctuates about the setpoint due to the
rotation of the load in the drum 18 and imbalance in the load. It
is also understood that the drum 18 may initiate rotation prior to
116, although it is also possible for the drum 18 to commence
rotation only at 116.
[0053] FIG. 8 provides a flow chart of an embodiment of a method
120 that employs the above theory for optimizing rotational speed
of the drum 18. The sequence of steps depicted is for illustrative
purposes only and is not meant to limit the method 120 in any way
as it is understood that the steps may proceed in a different
logical order, additional or intervening steps may be included, or
described steps may be divided into multiple steps, without
detracting from the invention. The method 20 may be incorporated
into a treating cycle of the washing machine 10, such as during a
specific treating phase, for example a wash phase or a tumble wash
phase, or may be performed independently from a treating cycle. It
is assumed that a load of one or more articles has been placed
within the drum 18 prior to commencement of the method 120.
[0054] The method 120 may begin with at 122 with initiating
rotation of the drum 18. The initial rotational speed may be one
suitable to induce tumbling of the load. An exemplary initial speed
is 25 RPM. Rotating of the drum 18 may occur subsequent to or
simultaneously with the wetting of the load by the liquid supply
and recirculation system (not shown). In the washing machine 10 of
FIG. 2, the motor 26 may drive the rotation of the drum 18.
[0055] According to one embodiment, the motor 26 rotates the drum
18 at the initial speed at a steady state for at least a portion of
122. For example, the drum 18 may rotate according to a constant
speed setpoint, wherein the motor 26 is controlled to rotate the
drum 18 according to a constant speed while the actual speed of the
drum 18 fluctuates about the constant speed setpoint due to the
rotation of the load in the drum 18 and imbalance in the load.
[0056] At 124, the current crest factor is determined from the
waveform of the motor torque signature for the motor 26 operating
to rotate the drum 18 at the initial speed.
[0057] At 126, the current crest factor is compared to a past crest
factor. The past crest factor is the crest factor determined prior
to the current crest factor, or is the previous current crest
factor determined in the previous cycle though the method 120. In
the first cycle through the method 120, the past crest factor is
equal to zero.
[0058] If it is determined that the current crest factor is not
greater than the past crest factor, the method 120 moves on to 128,
in which the rotational speed of the drum 18 is decreased. The
method 120 then returns to 124.
[0059] If it is determined that the current crest factor is greater
than the past crest factor, the method moves on to 130 to determine
if the rotational speed has been optimized. The rotational speed is
considered to be optimized when the crest factor is maximized
because this means that the mechanical energy due to falling action
being imparted to the articles is also maximized. If it is
determined that the rotational speed has not been optimized, the
method 120 moves on to 132, and the rotational speed is
increased.
[0060] If there is no past crest factor, i.e. past crest factor=0,
as the case would be the first time the current crest factor is
determined at 124, the method 120 will cycle through 130 and 132 to
return to 124.
[0061] At 128 or 132, the rotational speed may be changed (i.e.
increased or decreased) in predetermined increments. A preset
scheme for increasing/decreasing the rotational speed may be
programmed into the controller 70. For example, the rotational
speed may be changed in smaller increments each time the method 120
cycles through 128 or 132.
[0062] The maximum crest factor can be determined by cycling
through the method 120 until the a maximum crest factor is reached,
or by cycling through the method 120 a preset number of times, i.e.
a present number of drum rotational speed changes, that is
estimated to reach the maximum crest factor within a certain degree
of accuracy, for example .+-.5%. The estimation of the number of
times the method must be cycled through to reach the maximum crest
factor within a certain degree of accuracy may be predetermined
based on empirical testing.
[0063] The rotational speed associated with the maximum crest
factor may be used to control the rotational speed of the drum as
desired, which may be considered the "optimum" for that particular
treating cycle or treating cycle phase. In most cases, the actual
rotational speed will be set to the rotational speed corresponding
to the maximum crest factor to obtain the most mechanical energy
imparted to the system because, all things being considered,
horizontal axis machines input relatively small amounts of
mechanical energy, even at their maximum. If the rotational speed
has been optimized, the method 120 may end, or the method may
return to 124. If the later is the case, at least 128 and 130 may
be periodically run during the treating cycle to make sure
rotational speed remains optimized.
[0064] One or more of the methods 90, 110, 120 discloses herein may
be performed for or during a single treating cycle. For example,
methods 90 and 120 could be combined such that the crest factor
determination could be used to both determine when to terminate a
portion of the treating cycle, as outlined in method 90, and to
optimize rotational speed of the drum, as outlined in method 120.
These two methods 90, 120 may easily work in together since one way
of determining the cumulative value indicative of cumulative
mechanism energy due to falling action, as required at 94 of method
90, is by determining crest factor, as done at 124 of method
120.
[0065] The embodiments of the method function to determine an
optimum rotational speed that maximizes the mechanical agitation of
the load. This can provide better article care and reduce wear on
the articles since the exposure of the load to movement, heat, and
treating chemistry is limited to the amount of time needed for
optimum cleaning. Furthermore, the washing machine 10 may be more
energy efficient since rotational speed is optimized.
[0066] While the invention has been specifically described in
connection with certain specific embodiments thereof, it is to be
understood that this is by way of illustration and not of
limitation. Reasonable variation and modification are possible
within the scope of the forgoing disclosure and drawings without
departing from the spirit of the invention which is defined in the
appended claims.
* * * * *